A polycarbonate resin is excellent in mechanical properties such as impact resistance and is also excellent in heat resistance and transparency, and therefore, the polycarbonate resin is used in various fields such as an electric field, an electronic field, an office automation apparatus field, a machine field, and an automobile field. However, there is a problem that a raw material of the polycarbonate resin is derived from petroleum, so environmental load thereof is large, which has recently been a problem, from the viewpoint of degradability of the polycarbonate resin after use.
On the other hand, there are many aliphatic polyester resins which have biodegradability, and those resins have been greatly drawing attention from the viewpoint of concern for the environment after use. In particular, from the point that a polylactic acid resin made from a raw material derived from a plant such as corn or sugarcane is finally decomposed into water and carbon dioxide (carbon neutral), the environmental load can be decreased, and thus, a development of the polylactic acid resin is being undertaken as an environment-responsive resin. Further, the polylactic acid resin has high melting point as a plant-based plastic and is capable of being melt-molded, and hence utilization of the polylactic acid resin is expected as a plant-based and biodegradable resin excellent in practical use. Further, there are also some resins among aliphatic polyester resins derived from petroleum, in which a part to the whole of the raw materials thereof are to be changed to plant-derived ones in the future, which has been drawing attention.
However, the aliphatic polyester resins including a polylactic acid are low in mechanical physical properties especially heat resistance, and therefore, it is difficult to use a single aliphatic polyester resin as a molded article in the part which requires mechanical strength.
Hence, there has been an attempt to solve the above-mentioned problems by alloying the aliphatic polyester resin with an aromatic polycarbonate.
On the other hand, as one of the methods of improving mechanical properties and heat resistance of the aliphatic polyester resins, a method of using inorganic fillers such as a glass fiber and a carbon fiber has been studied. However, a large amount thereof needs to be added to the aliphatic polyester resins, and thus, there are problems in that: fluidity of the composition is decreased; density of the molded article is increased; residual materials that result in wastes when they are incinerated or discarded are increased and environmental load is increased; and the like. Accordingly, utilization of an organic filler has been studied, and for example, Patent Document 1 describes that an organic filler derived from a natural product is added to a polyester resin including a polylactic acid. However, the Patent Document 1 also describes that a resin composition not having a polymer containing an epoxy group-containing vinylic unit has inferior moldability and surface appearance.
Hence, there has not yet been known any aromatic polycarbonate resin composition which has small density, is excellent in rigidity and fluidity, and has good external appearance.    Patent Document 1: JP 2006-117768 A